/**
 * 
 */
package com.designpattern.design.facade;

/**
 * 屏幕
 * @author zhangyang
 *
 */
public class Screen {

	private static  Screen instance = new Screen();

	public static Screen getInstance() {
		return instance;
	}
	
	public void up() {
		System.out.println("屏幕上升");
	}
	
	public void down() {
		System.out.println("屏幕下降");
	}
	
}
